#!/Library/Frameworks/Python.framework/Versions/3.8/bin/python3
# -*- coding: UTF-8 -*-

s1="this sentence's length is 40 just right."
msg1=s1.capitalize() # 字符串第一个字符转为大写
msg2=s1.title() # 字符串每个单词大写
msg3=s1.upper() # 全部字母大写
msg4=s1.lower() # 全部字母小写
print(msg1,msg2,msg3,msg4,end="23" ,sep="[]") 